Commuity input on biothem reader design

edited February 2015 in RFID/NFC
As mentioned in another thread, I'm building a new reader for the biothem chip (yes, I created a new account, I decided I should use my name rather than a handle if I'm going to be selling stuff), since the only current readers are very animal oriented and not ideal when using the chip in humans.

The current system I've designed consists of a coil antenna, an RFID decoder chip, an arduino nano, a bluetooth module and a battery. also an android app for viewing the data and configuring the reader.

Since I figure there will probably be at least a few people who want this system, I should ask exactly what people would like to see in the final design.
Feel free to suggest anything, but things I'm particularly interested in hearing about are:

case shape/design. currently the plan is to 3d print cases. right now I'm just dealing with a flat-ish rectangle, with slots on two sides where a strap can be fitted to hold the reader in place on an arm or leg. any suggestions?

battery life/size/shape/weight. naturally longer run time is better, but having a larger battery costs more, takes more space and is heavier. what trade off do people want? one thing to point out is there are two modes of operation: 1) only read the temperature when the user presses a button, 2) read the temperature every few seconds/minutes (as configured by the user), the more frequently you read the temperature, the more power is used. personally I feel it would be good to run for around 12 hours, while reading once a minute, but that requires a reasonably large battery. thoughts?

other possibilities which might be cool, but may make the system cost more, for now I'm not planning to include these features, but if there is enough interest I will, and for software features I can add them later if people want them.
standalone mode: rather than only sending the data to a smartphone, the reader could have added storage to save values read, and transmit them in bulk later.

apps for other OSes: right now I'm only working on android, but I could build apps for iOS/windows/linux etc. apps are free, but I'll need to change more for the reader to account for the time for me to build each app. I will opensource the android app, so if you'd rather, you can port it to other devices yourself.

built in display: currently the only way to view the temperature value is on the smartphone, I could add a small display to the reader to allow reading value without needing a smartphone.

more ways to export data: currently the app lets you view temperature values, save them to a file and send them in an email. I could add things like facebook sharing etc. personally I don't want that kind of feature, but maybe other people do?

depending on which features we go with, I'm hoping to keep the price at no more than $100, but if people want every possible feature, it will cost more.

This is your chance to choose the reader design, tell me what you want and I'll try to make it happen



  • I would LOVE to get this upgrade once it becomes available! Everything you've listed out sounds pretty exciting, and I cant wait to get to give it a shot.

    As far as the mode of operation, I personally see myself spot-checking with it as opposed to having constantly running feedback.

    Setting up output on the device itself could mitigate the need for smartphone apps. I'm already in the Android boat though, so sticking with the current app-based system works fine for me.

    The case sounds perfect. Simple and doesn't interfere with function. I can always dress it up with stickers and such if I want to get fancy :)
  • @BirdMachine cool. what's your opinion on battery size? even if you don't plan to run it all the time, would you rather a smaller or larger battery?
  • I think it depends on how much bigger or smaller. I imagine that everything from a watch battery to a phone-style li-on means it can still be quite portable. 

    I'd like to be able to keep it in my Bag of Many Wondrous Things, without having to remove and replace or charge up every other day. If that means going with a bigger battery, I am all for the size tradeoff. The bag is quite large; I'm sure I'll be able to make room. 
  • Automated periodic reading would be the main reason for me to buy this and keeping a record I can output to a spreadsheet would be ideal. If that spreadsheet is automatically pushed to Dropbox I will sign my check today.

    I would like to see this powered by a standard 9V battery. 9V rechargeable batteries already exist and I can buy one at the gas station if I have a dead battery. The folks who only want to spot check don't have to shell out the cash for a rechargeable while people who want to steam five times per minute can carry all the batteries they want. If you don't have to factor the cost of a LiPO battery it will be easier to keep it under $100.

    I think these are usually implanted in the upper arm, right? Here is a thought about size/shape. If the antenna can be made roughly the same size as an iPhone it would be easy to order an iPhone sport armband to hold it in place comfortably. The rest of the device would reside outside of the case. Imagine hanging a man's bi-fold wallet out of a pocket.

    I have used 16x2 character displays with Arduinos in the past and they're easy to program. Not to mention cheap.

    @BirdMachine What do you have in your Bag of Many Wondrous Things?
  • I think alot of the design decisions are going to depend on where the standard implantation site ends up being.  It was said in another thread that the SfM crew had been testing a new implantation site (rather than the standard hand placement for RFID) and that @kjwx has his in his upper arm.  I'm actually currently envisioning a mid-forearm placement (dorsal side) for myself unless some compelling reason leads me to reject that spot.

    As of this moment, I'm thinking of it more as a spot-check type of thing rather than a continuous scan, but my opinions on that could change with time.  I'm an Android user so your current method of display works for me but I would be interested in an onboard display for the reader, too.
  • Yes, I also envisaged spot checking over continuous monitoring, which to me suggests the need for built-in display. I think
    a screen is needed to make it quick to check temperature at any time, if you need to get your phone and load the app, it takes time, admittedly not much, depends if that would bother you. Obviously it could still stream to a smart phone.

    How feasible is a clip-on display within the same budget?

  • @McSTUFF yes, not having to include a battery would make things cheaper/easier, and it would leave people the option to carry whatever size battery suits their needs. But then the battery would be outside the case, how would it be held in place? right now the device is charged via micro-USB, so you can still pug in an external usb battery pack.

    @aviin SfM are testing the biothem chip implanted in the thigh, so far there have been no issues with any placement tried, as far as we know it's fine the put it wherever you want.

    @Everyone the display itself is cheap, totally within budget, I'm just a little worried about how much work it will be to assemble. But given how lots of people want this, I'll add it to the design.
  • edited July 2015
    I know you really want to see a finished device, but the best I can do is show you my development board:

    also possibly of interest to some people, here is the insides of the pet read some of us are currently using until the custom reader is ready.

  • I've been really busy but have some time now. I've been looking at what screen to use, and although it's a couple of dollars more, I think I'll go with an OLED display, something like this, it's smaller in size, requires less power, and has far better resolution.
  • Can't wait to see how this thing turns out.  I've got my Halo scanner on order but something a little sexier will be nice :)
  • Source code for alpha version of the android app, it's very limited, just displays the temperature sent from the reader, I'll update it soon-ish, can be found on github here

    Now I just need to get design a decent looking case for it:
  • Very nice, so apparently it is readable without using super sized coils. Does it transmit the temperature to the android device via Bluetooth?
  • Yes, it uses bluetooth to connect with android.

    Yeah, the smaller coil is good for the size of the device, but it doesn't have a very good range, only 1-2cm, a big coil can get around 10cm, it's a trade off, but I wanted to keep this device as small as possible.
  • edited February 2015
    If I was to design this for logging body temp, I would make the coil a patch to could stick to your clothes, then have the reader mounted on your belt or in a pocket. The only problem I see with that would be snagging the wires on stuff, but you could also place it on the inside of your shirt so that would be mitigated. But I really have no idea if you could even have the coil that far away from the actual reader itself.

    I do like the idea of a small handheld devices though, something slim and streamlined. But that would also mean small coils like you said. As far as batteries go, would something like a cell phone battery work? It's already pretty small and would last for quite a long time. And since the batteries are standard it would be easy to pick up another. But if this amount of current isn't needed something with a smaller size would be ideal.
  • edited February 2015
    Yeah, I want to keep it as small as possible, sadly that limits the read range, but for this version it's a trade off I'm willing to make.

    this is the battery I'm using to power the system:
  • It's all sounding/looking very cool and I'm looking forward to its release.  Awesome.

    Here's something to maybe consider regarding design.  Is it feasible (or even worthwhile) to add a small port where a larger antenna coil could be plugged into the device?  I'm not sure of the need here, though.  If it were an option to buy a secondary larger coil with the device, though, I'd buy it.
  • @aviin an external antenna is not really an option with the current design, but I'll keep it in mind for the future.
  • edited February 2015
    depending on how you are putting all the parts together, and how big the next size of coils are, I see no problem with going to a larger size.

    Now I could be horribly wrong but couldn't you just sit the coil down on top of the battery in whatever housing you are using? think of the way wireless chargers are positioned in phones.

    Along the same line of phones, its not a 2d shape, remember you have depth to play with. people will feel length and width changes in their phones, but a change in depth? hardly.

    How thick will this thing be? a cm maybe? I know those boards aren't that thick, stack that coil on top of that battery, slide some protective film between those boards and make one stack of two with that long board running along the side in a single stack. I would think that would sit right about at a cm thick.

    I would take the bottom left board, get rid of those header pins, and stack it on top of the board on the top right. Than take that and run it along the top edge of the battery pictured. Take the top left board and run it along one of the side edges of the battery. and take your coil and place it on top of your battery/board surface. Place in your chosen packaging and tada! you may even have enough space to fit a bigger coil like I said depending on what the next size up is.
  • edited February 2015

    @Avanthus the reason I can't switch to a larger coil is that coil and the rfid pcd is one single block, potted together :(, I'd need to change the whole rfid module, which is why I want to leave it for a future version... but if this is really important to people, I can change this version, but it will delay things at least a couple of months.

    yes, your description for putting the boards together is almost exactly what I'm planning.

    here is the alpha version all put together, it's pretty big/ugly, but that will improve, it's just over 1cm thick, and the size of a credit card. but the final version should be about 1/3 smaller


    btw, I'll bring this prototype to Grindfest Zero, so you an try it out there if you like (assuming you have a biothermo implant of course)
  • Hi guys,

    This reader is looking interesting for sure... but I'm curious about those of you who mention constant temp monitoring. Why would you opt for such an invasive method of temperature monitoring when it would be very easy, cheaper, and more reliable to simply use a recording thermometer strapped to your arm? These things exist already and don't require implanting a tag which has biobond on it - something that makes removal or replacement very difficult.

    I'm not meaning to sound abrasive, I'm just wondering if there is a practical reason to use an implanted biotherm tag and external reader strapped to your body vs just using a thermometer strapped to your body? Is it simply excitement over having a biotherm tag and wanting to use it, or is there something more here?
  • amal I agree, in purely utilitarian terms, don't think biothermo chips are worth it. They may offer slightly more accuracy since they are less skewered by the air temperature, but given the costs involved with implanting them, it's not worth it.

    I can't speak for anyone else, but the main reason I have one is because I think it's cool. I want to be on the bleeding edge (haha) of cybernetics advancement. Right now I don't think we have any implants that are truly worth it, in practical terms, but I want to push the boundaries, and be the first to try new things.
  • edited March 2015
    @alexsmith yeah thanks for clarifying. I think it's cool too and I'm probably going to get one implanted in my arm pit, but only after manually ejecting the tag and removing the biobond cap, re-cleaning it, then injecting. I don't plan on autoclaving it because I think it may damage the thermal sensor.

    As for the utility of implantables in general, I disagree. I totally think the access control aspects of implantable tags are "worth it" simply because the risk is extremely low and I use my implants for access control multiple times a day, every single day... but thats me.

    To bring this back to biotherms - if an access controller could be created that read the chip ID and also supplied temp data in an attempt to confirm some sort of life (tag is not in a dead limb or ripped out of a person), then it might be an interesting twist. As you are working on a reader design meant for handheld use, I think I will stay away from that angle and focus on an access controller for these chips... possibly bring some new utility to the thermal readings.
  • amal Just fyi about removing the biobond cap. I tried this. it is very easy to remove by hand, simply 'peel' the cap away from the glass.

    I considered doing this to all the biothemo chips and having the re-sterilized before selling them, but as @glims pointed out, microscopic particles of bioboned may remain on the glass, which could lead to a build up of bacteria and rejection. Which is why I didn't do this. Not to say you shouldn't try it, but make sure you understand the risks.
  • edited March 2015
    @alexsmith ahh good point. Yeah, I'm not so concerned about the biofouling aspect since I will likely remove the tag after a year or so of testing in the armpit area. Alternatively, if I choose to keep it longer and it rejects, I won't be so bummed. Overall I'm not sure why microscopic bits of biobond material would result in more bacterial build-up than an entire cap of the stuff, but I'll talk to @glims about it... thanks for the heads up.

    Once we have a workable access controller solution that uses temperature and ID number, I may consider implanting one in my hand, and at that point I'd probably leave the biobond cap on... probably.
  • amal I've been thinking about what you said about using the temperature to verify that the chip is still implanted. I'm afraid that you may take this the wrong way and think I'm trying to undermine your position, but I think it's better for everyone that I say it now, rather than later after you build a system like that. While the concept of using bio-metrics in authentication is well established, and I agree that using it in combination with an rfid would work well, the biothermo chip doesn't work for this.

    The reason being that the there is no challenge response authentication used when reading the biothemo chips, unlike like say the NTAG216 NFC chips. This means that it's quite simple for me to use a proxmark3 to spoof both the chip ID and temperature at the same time. 

    I.E. using a biothemo can never be any more secure than an ordinary T5577 chip. If you really want to do this, I suggest designing a new chip with some type of crypto to verify the  bio-metrics.

  • @AlexSmith no problem at all, I totally agree. It was just a thought about what might be possible using biotherms. A new tag design that is much more secure is on the drawing board actually... but I also have some ideas on basic commercial access controller replacements that can use a wide range of tag types to their fullest capabilities, including tags never designed as access control tokens. As you said, a biotherm is as secure as the T5577 or EM4102 for that matter - that is to say not at all. However, even now many new access control systems coming out today opt to lock in at this level of non-security... the problem I have with them is that they offer no choice to the customer or end users to upgrade that security level by using a better more capable tag.. you are typically locked into a single solution tag type, take it or leave it.

    I am looking at building a multifreq access controller that lets you bring what you have to the table and it will attempt to use the most secure options possible for that tag type. All you have is a biotherm chip? You can use it, and we'll try to make it as secure as possible while we're at it. Petty thugs rip your tag out? Won't work because it's too cold. Alex dropped by for some tea with a funny looking briefcase, you're screwed. Of course, not real security, but the best possible security for the tag type being used.

    Anyway, all thoughts at this point... some design chunks floating around, but they will coalesce soon enough I'm sure.
  • Hi Guys,

    I've been looking into this for a while and thought I'd add my 2 cents into readers..

    Personally, I'd prefer a doorway reader that reads every time I walk through the door. 

    I've done some basic analysis and think it should be only a few loops of wire going around the entire doorway. From there, you could make some kind of bluetooth/zigbee/bluetooth device which could send it to a database... 

    Food for thought.


  • Jhkier that may be doable. How many people would want a door frame reader? I have lots of other things to work on, so unless lots of people want this, I probably won't bother building it.
  • I would love the doorframe idea. I may eventually want it to be read more often, but I love the concept and it would definitely help prove a lot of other concepts.
  • Hi Alex,

    If you build the module which was BLE (Bluetooth Low energy) and had the ability to 'plugin' two wires to extend the induction coil, we could easily run some wire in a loop and plug it in... It could be a multi purpose device. 

    We'd need to do some test, but I'm guessing its more about the number of 'loops' required than anything else... 

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